The present invention relates to hydrostatic load relief, and more particularly, to the load relief of a load bearing threaded spindle which is moved axially upon rotation of a meshing threaded member.
Lift devices of the type referred to above are known. The spindle in these devices is usually permitted to move axially while being prevented from rotation. The female member receiving the spindle is driven externally and is, of course, mounted for rotation in a suitable frame, stand, or the like. Other devices have a stationary threaded female member and a rotating spindle. It is also known to hydrostatically load-releave the load bearing spindle in that the threads of the female member have oil pockets which receive pressurized oil from a pump for taking up some of the load the spindle exerts upon the female threaded member.
It was found that feeding the oil to the pockets presents no problems, if the threaded member is stationary and the spindle rotates. However, if the female members turns, the oil transfer to the pockets is troublesome. At the very least, one needs special sealing means to avoid losses in the radial oil feed to and into the rotating member.